Luminaries for outdoor use usually need a certain level of IP protection, for example, IP65 or a higher level. To meet such needs, luminaries, such as the LED products need to be sealed to prevent water from entering the LED products. For LED linear light source, a common point of existing solution is to use a glue to pot and seal an end cap. For example, one solution in the prior art is that a glue is used to seal an end cap firstly and then potting material is potted directly at the LED, thereby realizing encapsulating the lighting device. Its weakness is that there exists color difference and bubbles on the LED surface. Another solution in the prior art is that the end cap is first sealed and then potting material is potted to the cover in which a circuit board mounted with multiple lighting modules is arranged. Its weakness is that there are too many assembling steps.